February 3, 2012

Study Highlights Potential Link Between ADHD and Anesthesia

by editor

According to a new study from a leading U.S. medical research center, children are more likely to develop attention-deficit hyperactivity disorder (ADHD) if they receive anesthesia more than once at a young age.

ADHD is a developmental disorder that typically appears in children before the age of seven. As the name indicates, it is usually characterized by a combination of hyperactivity, inability to concentrate on single tasks and difficulty controlling impulsive behavior.

Scientists at the Mayo Clinic in Rochester, Minnesota found that children who underwent anesthesia multiple times before age 3 went on to develop ADHD more than two and a half times as often as kids who had never received anesthesia.

According to the researchers, this study is just one of many in recent years to draw attention to the adverse effects of anesthesia on the developing mammalian brain.

One of the study´s co-authors Dr. David Warner noted that the team was initially unsure whether their results would square with those of other recent studies focusing on the long-term cognitive effects of anesthesia.

“We were skeptical that the findings in animals would correlate with kids, but it appears that it does,” said Warner, a pediatric anesthesiologist at the Mayo Clinic.

The research team scoured the medical records of nearly 5,300 children born between 1976 and 1982. After identifying 341 children who had been diagnosed with ADHD, they ploughed deeper into the data to determine how many of these children had received anesthesia prior to age 3.

What they found was a significant differential between ADHD and non-ADHD children: Roughly 7 percent of the children who had not been exposed to anesthesia before age 3 had gone on to develop ADHD compared with 18 percent of those who had.

Yet despite the strong correlation between the ADHD and receiving anesthesia at a young age, Warner was quick to point out that their results do not prove that anesthesia causes ADHD.

“A wide range of other factors might be responsible for the higher frequency of ADHD in children with multiple exposures,” he said.

“We need to do more work to confirm whether this is really a problem in children or not,” Warner added. “We can´t exclude there is a problem, but we also haven´t determined there is a problem.”

Dr. Deborah Culley of Harvard Medical School agrees.

In an editorial piece that appeared Thursday alongside Warner´s study in the Mayo Clinic Proceedings, Culley wrote a word of caution to pediatric physicians who might be tempted to precipitously change their practices based on the results of this study.

“The decision to proceed with surgery with anesthesia in an infant is best made based on what is known about the indications for–and benefits of–the procedure and general anesthetic, rather than what is unknown but feared,” she cautioned.

Culley added that doctors should nonetheless always exercise parsimony in striving to keep infants´ exposure to anesthesia to a bare, if necessary, minimum.